precision lowp float;

varying vec2 vUv;
varying float vElevation;

//取样纹理
uniform sampler2D uTexture;

void main() {
    vec4 textureColor = texture2D(uTexture, vUv);
    float height = vElevation * 2.0 + 0.4;//0-0.8
    textureColor.rgb *= height + 0.9;
    gl_FragColor = textureColor;
}